Important Changes to Tiling Standards

[Time's Ran Out]

Ask the client how to set the room out!
That’s why they are paying you - to do a professional job.
Clients away on holiday, that’s okay I’ll send him a photo of how it’s going to look - he’s going to be really confident in your ability.
What’s been done is sh*te and these chancers do our trade no favours.

 

[acaciaguy]

I agree John. I advise clients on what I wil do and look best. However they are the ones that have to look at it forever. If they are happy i am

To avoid any conflation of posts. I agree John the work op posted is rubbish

 

[peterwhayward]

I would say that almost all of my bathroom jobs have a cut or trimmed tile at the bath ( or shower tray)to avoid that awful finish at ceiling level or anywhere else.

 

[Soso]

Hello all,

I have a query regarding the British standards. I note that they say the following below about notched towelling method. What is confusing me is the bit about 50% contact. Surely this is 50% while its being placed on the wall but that the twisting and sliding action should result in 100% coverage ? I have a builder trying to justify dot and dab based on this wording. Or trying to justify not covering the whole tile.

Also, can i also assume that 50% contact still means that 100% of the wall should be covered in adhesive...the 50% is just the ribs sticking out of the adhesive from trowelling?

Second question is that i just need to be able to explain the difference between back buttering and dot and dab in layman terms for a judge. Can anyone help me ?

Notched trowelling method
Adhesives should be applied to the background with a trowel as a floated coat, the adhesive should be pressed into the surface, and combed through with a suitably designed notched trowel of the type recommended by the adhesive manufacturer: this gives a series of ribs into which the dry tiles should be pressed with a twisting or sliding action; this operation has to be carried out correctly to ensure that the adhesive wets the back of the tile and achieves an area of contact of at least 50%, spread evenly over the back of the tile.
Whatever type of trowel is used, it should apply the adhesive
in a manner such that the finished bed thickness is no greater than that recommended by the manufacturer and that maximum practical contact between tile and adhesive is achieved.
The period of time during which tiles can be adequately bedded after spreading the adhesive is approximately 20 min but this varies according to the prevailing atmospheric conditions. It is important that more adhesive should not be spread on the wall than can be covered with tiles within the open time.
NOTE 1 The amount of adhesive used and the height of the ribs obtained are governed by the angle at which the trowel is held against the surface. The amount of contact is also dependent on the twisting or sliding of the tiles as they are pressed onto the ribs of adhesive.
NOTE 2 It is good practice to remove a tile occasionally as fixing proceeds to check that adequate contact and wetting is being maintained with the adhesive.

 

[Tile Shop]

BS5385 part 1, 2018
7.1.2 - Bedding materials:
blah blah....
Tiles should not be fixed using the dot and dab technique.

So important, they repeat it in 7.2.1.6 - Tile joints
Tiles should not be fixed using the dot and dab technique.

Think your 50% spread is also out of date:
6.2.3.1 - General
Tiles with a surface area of 0.1 m2, should be solidly bedded.
Tiles with a surface area of less than 0.1 m2, but which weigh more per square metre than 70% of the background's capacity to carry the weight, should be solidly bedded.

Your exact wording above from 7.2.1.5.1 Notched Trowelling method, "this operation has to be carried out correctly to ensure that the adhesive wets the back of the tile and achieves an area of contact of at least 50%, spread evenly over the back of the tile". - This sentence was removed in the last 2018 update.

So yeah, your builder is wrong! Sack him and get yourself someone who knows what they are doing.

 

[Dumbo]

Have you a failure or are worried about future failure .
But as above if he is still working stop him ..
What is the value of your work if it several thousand it may be worth getting a tta report on the work.

 

[Old Mod]

I’m so glad you saw this @Paul C.
I knew I’d seen this written somewhere, and was about to go hunting.

 

[Soso]

BS5385 part 1, 2018
7.1.2 - Bedding materials:
blah blah....
Tiles should not be fixed using the dot and dab technique.

So important, they repeat it in 7.2.1.6 - Tile joints
Tiles should not be fixed using the dot and dab technique.

Think your 50% spread is also out of date:
6.2.3.1 - General
Tiles with a surface area of 0.1 m2, should be solidly bedded.
Tiles with a surface area of less than 0.1 m2, but which weigh more per square metre than 70% of the background's capacity to carry the weight, should be solidly bedded.

Your exact wording above from 7.2.1.5.1 Notched Trowelling method, "this operation has to be carried out correctly to ensure that the adhesive wets the back of the tile and achieves an area of contact of at least 50%, spread evenly over the back of the tile". - This sentence was removed in the last 2018 update.

So yeah, your builder is wrong! Sack him and get yourself someone who knows what they are doing.

Believe it or not Paul, this builder is arguing that he did the work in May 2018 and therefore the June 2018 version of the text which came out in june itself doesn't apply and he wouldn't have known about it. So he is trying to warp what the sentence i the bsi 2009 version which is the 50% coverage....while happily ignoring the words (spread evenly on the back of the tile).

My assumption, and this is what i need help on a little is that this 50% is the ribs a notched trowel would create. The wall would be covered in adhesive too. And when the tile is pushed into the ribs, it will spread and cover 100% of the tile ?

 

[Tony_C]

Think of back buttering as you would butter toast, skimming a thin layer over it. Not dabbing 5 blobs

EDIT:

This isn't to replace serating the wall/floor. It's to help with better coverage also when setting the tile into the ribs. I should have added that

 

[Soso]

Think of back buttering as you would butter toast, skimming a thin layer over it. Not dabbing 5 blobs

OMG Tony, that is perfect !!! I hadn't even thought of it that way but that would make anyone understand !!! Thank you so so much

 

[Soso]

Have you a failure or are worried about future failure .
But as above if he is still working stop him ..
What is the value of your work if it several thousand it may be worth getting a tta report on the work.

Thanks jcrtiling. We are in court at the moment sadly. Been ongoing for a year and I think this person is likely to only stop all this if the TTA do a report - completely agree

 

[J Sid]

BS 5385-1:2009
7.2.1.5 Application of adhesive and tiles
7.2.1.5.1 Notched trowelling method For situations where dry conditions prevail after tiling is completed, the notched trowelling method should be used. The final bed thickness of the cement-based adhesive should not exceed 3 mm; if it is used at a thickness greater than this, excessive stresses might develop possibly resulting in cracking of the tiles and/or adhesion failure. The adhesive should be applied to the surface as a floated coat with a trowel, pressing the adhesive into the surface, to give a bed
thickness of approximately 3 mm, which should then be combed through with a notched trowel of the type recommended by the adhesive manufacturer: this gives a series of ribs into which the dry tiles should be pressed with a twisting or sliding action; this operation has to be carried out correctly to ensure that the adhesive wets the back of the tile and achieves an area of contact of at least 50%, spread evenly over the back of the tile. Tiles should be fixed before surface drying of the ribbed adhesive bed prevents the adhesive wetting the back of the tiles: the open time varies according to the prevailing atmospheric conditions and is usually about 20 min; it is important not to spread more adhesive on the wall than can be covered with tiles within the open time of the adhesive.
7.2.1.5.2 Buttering method The buttering method can be used for occasional awkward tiling positions, e.g. around openings and restricted areas where a notched trowel cannot be used; where this technique has to be adopted, the adhesive should be spread evenly over the whole of the back of each dry tile with a trowel. The bed thickness should be slightly greater than the final thickness required so that when each tile is pressed or tapped firmly into position the correct thickness is achieved. The thickness should not be greater than the maximum recommended by the manufacturer of the adhesive. Care should be taken to ensure that as far as possible no voids are left behind the tiles.
7.2.1.5.3 Notched trowelling and buttering method The notched trowelling and buttering method combines 7.2.1.5.1 and 7.2.1.5.2 and should be used for fixing large tiles (3.4) and tiles with ribbed, deep keyed or heavy buttoned back profiles. A thin coating of adhesive buttered over the backs should fill the deep keys before placing the tiles in position on the combed adhesive bed. There should be no significant increase in the bed thickness. NOTE This bedding method aims to achieve a solid bed

 

[Dumbo]

Other than the builder doing it wrong what are the problems that you actually have

 

[Tile Shop]

Sorry to bring this up late, but can we just clarify that this is a wall installation and not floor?

Also is it a wet or dry area?

 

[Soso]

BS 5385-1:2009
7.2.1.5 Application of adhesive and tiles
7.2.1.5.1 Notched trowelling method For situations where dry conditions prevail after tiling is completed, the notched trowelling method should be used. The final bed thickness of the cement-based adhesive should not exceed 3 mm; if it is used at a thickness greater than this, excessive stresses might develop possibly resulting in cracking of the tiles and/or adhesion failure. The adhesive should be applied to the surface as a floated coat with a trowel, pressing the adhesive into the surface, to give a bed
thickness of approximately 3 mm, which should then be combed through with a notched trowel of the type recommended by the adhesive manufacturer: this gives a series of ribs into which the dry tiles should be pressed with a twisting or sliding action; this operation has to be carried out correctly to ensure that the adhesive wets the back of the tile and achieves an area of contact of at least 50%, spread evenly over the back of the tile. Tiles should be fixed before surface drying of the ribbed adhesive bed prevents the adhesive wetting the back of the tiles: the open time varies according to the prevailing atmospheric conditions and is usually about 20 min; it is important not to spread more adhesive on the wall than can be covered with tiles within the open time of the adhesive.
7.2.1.5.2 Buttering method The buttering method can be used for occasional awkward tiling positions, e.g. around openings and restricted areas where a notched trowel cannot be used; where this technique has to be adopted, the adhesive should be spread evenly over the whole of the back of each dry tile with a trowel. The bed thickness should be slightly greater than the final thickness required so that when each tile is pressed or tapped firmly into position the correct thickness is achieved. The thickness should not be greater than the maximum recommended by the manufacturer of the adhesive. Care should be taken to ensure that as far as possible no voids are left behind the tiles.
7.2.1.5.3 Notched trowelling and buttering method The notched trowelling and buttering method combines 7.2.1.5.1 and 7.2.1.5.2 and should be used for fixing large tiles (3.4) and tiles with ribbed, deep keyed or heavy buttoned back profiles. A thin coating of adhesive buttered over the backs should fill the deep keys before placing the tiles in position on the combed adhesive bed. There should be no significant increase in the bed thickness. NOTE This bedding method aims to achieve a solid bed

Thank you Julian. I am hoping that the bit about "spread evenly over the back of the tile" and the fact that the entire wall needs to be covered in adhesive should be enough to bat this out. It's a shower area and there should be no voids and the areas should be solidly bedded which i believe part 4 of the standard also states. It's just that the 50% written here is mis-leading surely ?

 

[Soso]

Sorry to bring this up late, but can we just clarify that this is a wall installation and not floor?

Also is it a wet or dry area?

Hi Paul, It's in the bathroom which includes shower areas.
I know the part 4 7.2 section says that it should be solidly bedded but this builder is trying to use the whole 50% thing to say that the tile doesn't need to be fully covered over the back. It's wall tiles.

 

[Soso]

Other than the builder doing it wrong what are the problems that you actually have

So he is used dot and dab in the shower area also and so we can hear many voids behind the tiles. Also, he has gone so far as to dot and dab the sheet of mosaic ! He said that the grout would go into the gaps in the adhesive behind the tiles and lift them up into place...obviously we knew that at this point it was all a crock and we then started doing more research. But essentially it has left small peaks and troughs in the mosaic as well which he has then found ridiculously hard to grout and thus there are holes in the grout everywhere

 

[acaciaguy]

Can I ask if the wet areas have been suitably prepared... tanked etc prior to tiling.

 

[Tile Shop]

Thank you Julian. I am hoping that the bit about "spread evenly over the back of the tile" and the fact that the entire wall needs to be covered in adhesive should be enough to bat this out. It's a shower area and there should be no voids and the areas should be solidly bedded which i believe part 4 of the standard also states. It's just that the 50% written here is mis-leading surely ?

Not exactly, but it could be clearer that is for dry areas only for small format tiles. Dotting and dabbing is not spreading, so that's his argument already out the window regardless.

Initially, part 1 should be followed, but special considerations should be made in specific areas (which the 2009 standards didn't directly apply to), which is when anything in part 4 should be made a priority, until such time that any updates in part 1 match or exceed what part 4 recommends.

So if he was basing it on the 2009 standards, he should also refer to part 4, 2015, which says:
Section 7 - Wet and damp conditions:
7.2.2 Installations in high humidity areas:
Tiles should be solidly bedded in a water-resistant adhesive

7.2.3 Installations not immersed but subject to occasional wetting (reference made to domestic non-power showers)
a) Tiles should be solidly bedded in a water-resistant adhesive

7.2.4 Installations not immersed but subject to frequent wetting (reference made to wet-rooms, domestic power showers etc)
c) The tiles should be solidly bedded so that voids behind them are eliminated as far as possible

And if he doesn't know how to achieve solid bedding, he should revert back to part 1, 2009 to:
7.2.1.5.3 Notched trowelling and buttering method
The notched trowelling and buttering method combines 7.2.1.5.1 and 7.2.5.2 and should be used for large tiles (3.4 (mathematically refers to 60x30 upwards)) and tiles with ribbed, deep keyed or heavy buttoned back profiles. A thin coating of adhesive buttered over the backs should fill the deep keys before placing the tiles in position on the combed adhesive bed. There should be no significant increase in bed thickness.
Note This method aims to achieve a solid bed but, in practice a small number of voids are inevitable. (this doesn't mean a gaping 50% of no contact).

Also as @acaciaguy says, tanking is also advised under part 4, even before it became part of the 2018 part 1 update:
7.2.3 Note 1
For water sensitive backgrounds e.g. gypsum plaster, additional protection in the waterproof tanking system may be considered
Note 2 The use of impervious grouts and adhesives is no substitute for a tanked installation.

 

[Soso]

Can I ask if the wet areas have been suitably prepared... tanked etc prior to tiling.

No he used 9mm plasterboard on the wall the shower is attached to (i believe it was 9mm). He said he didn't need to tank it because he was using water resistant adhesive and grout and it will never have a failure and he has never had a leak and he doesn't need to tank it. Which i believe is incorrect. It was standards plasterboard btw.

The other wall was tiled before so he tiled over tile on that one

 

[Soso]

Not exactly, but it could be clearer that is for dry areas only for small format tiles. Dotting and dabbing is not spreading, so that's his argument already out the window regardless.

Initially, part 1 should be followed, but special considerations should be made in specific areas (which the 2009 standards didn't directly apply to), which is when anything in part 4 should be made a priority, until such time that any updates in part 1 match or exceed what part 4 recommends.

So if he was basing it on the 2009 standards, he should also refer to part 4, 2015, which says:
Section 7 - Wet and damp conditions:
7.2.2 Installations in high humidity areas:
Tiles should be solidly bedded in a water-resistant adhesive

7.2.3 Installations not immersed but subject to occasional wetting (reference made to domestic non-power showers)
a) Tiles should be solidly bedded in a water-resistant adhesive

7.2.4 Installations not immersed but subject to frequent wetting (reference made to wet-rooms, domestic power showers etc)
c) The tiles should be solidly bedded so that voids behind them are eliminated as far as possible

And if he doesn't know how to achieve solid bedding, he should revert back to part 1, 2009 to:
7.2.1.5.3 Notched trowelling and buttering method
The notched trowelling and buttering method combines 7.2.1.5.1 and 7.2.5.2 and should be used for large tiles (3.4 (mathematically refers to 60x30 upwards)) and tiles with ribbed, deep keyed or heavy buttoned back profiles. A thin coating of adhesive buttered over the backs should fill the deep keys before placing the tiles in position on the combed adhesive bed. There should be no significant increase in bed thickness.
Note This method aims to achieve a solid bed but, in practice a small number of voids are inevitable. (this doesn't mean a gaping 50% of no contact).

Also as @acaciaguy says, tanking is also advised under part 4, even before it became part of the 2018 part 1 update:
7.2.3 Note 1
For water sensitive backgrounds e.g. gypsum plaster, additional protection in the waterproof tanking system may be considered
Note 2 The use of impervious grouts and adhesives is no substitute for a tanked installation.

Paul C, Acaciaguy, oh my gosh i think this is everything I should need to be able to through his argument out. I think he must not realise that there is a part 4 for wet areas.

 

[acaciaguy]

No he used 9mm plasterboard on the wall the shower is attached to (i believe it was 9mm). He said he didn't need to tank it because he was using water resistant adhesive and grout and it will never have a failure and he has never had a leak and he doesn't need to tank it. Which i believe is incorrect. It was standards plasterboard btw.

The other wall was tiled before so he tiled over tile on that one

9mm is a bit thin in my opinion. Unless there is some special reason. However, the thickness issue is overshadowed by dot and dab etc I’m sorry to say the whole install is wrong.

To summarise (and please say if I’m wrong)

You have dot and dabbed tiles on 9mm standard plasterboard in a wet area with no tanking

 

[Soso]

9mm is a bit thin in my opinion. Unless there is some special reason. However, the thickness issue is overshadowed by dot and dab etc I’m sorry to say the whole install is wrong.

To summarise (and please say if I’m wrong)

You have dot and dabbed tiles on 9mm standard plasterboard in a wet area with no tanking

Yeap. That is exactly it. One wall is also tile over tile. AND he has dot and dabbed the mosaic section of the shower area leaving some peaks and troughs in the mosaic and lots and lots of holes because he has tried to push grout into the voids to lift the tiles into position.

 

[acaciaguy]

9mm is a bit thin in my opinion. Unless there is some special reason. However, the thickness issue is overshadowed by dot and dab etc I’m sorry to say the whole install is wrong.

To summarise (and please say if I’m wrong)

You have dot and dabbed tiles on 9mm standard plasterboard in a wet area with no tanking

In the year since you have had the work done. Have there been any visible issues? Are you hoping for a refund / rectified by builder. What’s the situation in terms of what you want as outcome

 

[Soso]

In the year since you have had the work done. Have there been any visible issues? Are you hoping for a refund / rectified by builder. What’s the situation in terms of what you want as outcome

Believe it or not, this person had threatened us with legal action for not giving him the final payment on his contract (he had had £4000 from us before the job had even really started (my mum is 75 and she gave it to him).

Anyway after a month of this happening, he dropped a claim form on us and we are now only just going to a preliminary hearing tomorrow to get the case heard. We have put a counterclaim in because we need to get the whole bathroom re-done really.

In terms of visible issues - we have put plastic sheets up over the mosaic so no issue there. Everywhere else, we don't know as i am the only one of 3 whole occasionally uses the shower now. My parents go next door as they are worried sick of a leak.